After having my partner color in dots for 20 dot cards of numbers 1–10, I just discovered that I can print onto 3x5 index cards from Microsoft word on my home printer.
I've used these to have students write or call out what is two more, two less, one more, or one less than the number shown. Sometimes I'll call out "make ten," and the student has to search for, write, or say the number that can be added to the number shown to make ten. I'm going to do ten-frame flash, as well, and show students the ten frame cards for about 3 seconds and have them write the number they saw and then check their responses against the stack. Having students identify how many blank spaces were on the flashed card is also a great way to get them thinking about pairs of numbers that make ten.